Implant with Improved Flow Characteristics

Abstract

An intervertebral implant comprising a body formed as an open truss structure, the body having a generally annular shape with a superior surface, an inferior surface, and a perimeter surface extending around an outer periphery of the body. The body may have a central portion and a peripheral portion, the peripheral portion extending inward from the perimeter surface toward the central portion, the peripheral portion including a first set of trusses, and the central portion including a second set of trusses. The implant may further include a strut at least partially defining a boundary between the central portion and the peripheral portion, wherein the strut has an oblong cross-sectional shape oriented to facilitate flow of bone graft material in a substantially radial direction away from the central axis.

1 . An intervertebral implant comprising:
 a body formed as an open truss structure;   the body having a generally annular shape with a superior surface, an inferior surface, and a perimeter surface, the perimeter surface extending around an outer periphery of the body about a central axis of the implant, and the implant defining a radial direction extending from the central axis to the perimeter surface;   the body having a central portion and a peripheral portion, the peripheral portion extending inward from the perimeter surface toward the central portion;   the peripheral portion including a first set of trusses; and   the central portion including a second set of trusses;   a strut at least partially defining a boundary between the central portion and the peripheral portion;   wherein the strut has an oblong cross-sectional shape oriented to facilitate flow of bone graft material in a substantially radial direction away from the central axis.   
     
     
         2 . The intervertebral implant of  claim 1 , wherein the central portion includes a central hollow portion devoid of struts and thus configured to receive bone graft material. 
     
     
         3 . The intervertebral implant of  claim 1 , wherein the peripheral portion is sized and configured to generally correspond to a cortical bone region of a confronting vertebral body. 
     
     
         4 . The intervertebral implant of  claim 1 , wherein the central portion is sized and configured to generally correspond to a cancellous bone region of a confronting vertebral body. 
     
     
         5 . The intervertebral implant of  claim 1 , wherein the peripheral portion includes a first set of trusses, the first set of trusses having a first density of trusses;
 wherein the central portion includes a second set of trusses, the second set of trusses having a second density of trusses; and   wherein the first density of trusses in the peripheral portion is greater than the second density of trusses in the central portion.   
     
     
         6 . The intervertebral implant of  claim 1 , wherein the strut has an airfoil cross-sectional shape. 
     
     
         7 . The intervertebral implant of  claim 1 , wherein the strut cooperates with other struts of the implant to direct bone graft material into a predetermined region of the peripheral portion of the implant. 
     
     
         8 . An intervertebral implant comprising:
 a body formed as an open truss structure;   the body having a generally annular shape with a superior surface, an inferior surface, and a perimeter surface, the perimeter surface extending around an outer periphery of the body about a central axis of the implant, and the implant defining a radial direction extending from the central axis to the perimeter surface;   the body having a central portion and a peripheral portion, the peripheral portion extending inward from the perimeter surface toward the central portion;   the peripheral portion including a first set of trusses defined by a plurality of struts; and   the central portion including a central hollow portion being devoid of struts.   
     
     
         9 . The intervertebral implant of  claim 8 , wherein the central hollow portion extends from an inferior side of the implant to a superior side of the implant. 
     
     
         10 . The intervertebral implant of  claim 9 , wherein the central hollow portion constitutes a substantial majority of the central portion of the implant. 
     
     
         11 . The intervertebral implant of  claim 8 , wherein the peripheral portion is sized and configured to generally correspond to a cortical bone region of a confronting vertebral body. 
     
     
         12 . The intervertebral implant of  claim 8 , wherein the central portion is sized and configured to generally correspond to a cancellous bone region of a confronting vertebral body. 
     
     
         13 . The intervertebral implant of  claim 8 , wherein the peripheral portion includes a first set of trusses, the first set of trusses having a first density of trusses;
 wherein the central portion includes a second set of trusses, the second set of trusses having a second density of trusses; and   wherein the first density of trusses in the peripheral portion is greater than the second density of trusses in the central portion.   
     
     
         14 . An intervertebral implant comprising:
 a body formed as an open truss structure;   the body having a generally annular shape with a superior surface, an inferior surface, and a perimeter surface, the perimeter surface extending around an outer periphery of the body about a central axis of the implant, and the implant defining a radial direction extending from the central axis to the perimeter surface;   the body having a central portion and a peripheral portion, the peripheral portion extending inward from the perimeter surface toward the central portion;   the peripheral portion being sized and configured to correspond with a cortical bone region of a vertebra and including a first set of trusses; and   the central portion being sized and configured to correspond with a cancellous bone region of a vertebra.   
     
     
         15 . The intervertebral implant of  claim 14 , wherein the central portion includes a central hollow portion devoid of struts and thus configured to receive bone graft material. 
     
     
         16 . The intervertebral implant of  claim 15 , wherein the central hollow portion extends from an inferior side of the implant to a superior side of the implant. 
     
     
         17 . The intervertebral implant of  claim 15 , wherein the central hollow portion constitutes a substantial majority of the central portion of the implant. 
     
     
         18 . The intervertebral implant of  claim 14 , further including a strut at least partially defining a boundary between the central portion and the peripheral portion;
 wherein the strut has a non-circular cross-sectional shape oriented to facilitate flow of bone graft material in a substantially radial direction away from the central axis.   
     
     
         19 . The intervertebral implant of  claim 18 , wherein the strut having a non-circular cross-sectional shape has a substantially airfoil-shaped cross-section. 
     
     
         20 . The intervertebral implant of  claim 18 , wherein the strut having a non-circular cross-sectional shape has a substantially oblong cross-section.